Friends don’t let friends wear offensive Halloween costumes. Isla Fisher knew Julianne Hough was flirting with disaster when she showed up to a Halloween party on Oct. 25 in blackface makeup, but her efforts to save the Dancing With the Stars alum from controversy turned out to be too little, too late.

A source reveals in the new issue of Us Weekly that the Great Gatsby actress, 37, “was mortified” when she saw Hough, 25, dressed as Orange Is the New Black character Crazy Eyes, complete with orange prison attire, a knotted ‘do, and darkened skin. (Crazy Eyes is played in the Netflix original series by Uzo Aduba.)

In an attempt to help, the Wedding Crashers comedienne recommended that Hough “go to the bathroom and wipe her face off,” the source says. (Fisher’s rep denies that she intervened.) “Isla hoped she got to Julianne before photos were taken,” the insider adds.

No such luck. Pictures of the Safe Haven star in costume quickly made the rounds online, sparking outrage and criticism. By the next day, the backlash was so intense that Hough felt compelled to issue an apology on Twitter.

“I am a huge fan of the show Orange Is the New Black, actress Uzo Aduba, and the character she has created,” Ryan Seacrest’s ex wrote on Oct. 26. “It certainly was never my intention to be disrespectful or demeaning to anyone in any way. I realize my costume hurt and offended people and I truly apologize.

Aduba’s OITNB costar Laverne Cox, for one, believes Hough simply didn’t know any better. “I wasn’t offended,” she revealed to Us a few days after the incident. “I thought it was a shame that she is in this country, that she would wear blackface and not understand the historical implications of that. I don’t think Julianne is making a specific informed choice to comment on blackness. I just think it’s out of this ignorance. That’s really sad.”